Richard Johnston b. GA
I don't know anything about your Richard Johnston, except he probably had some schooling along the way.If his daughter, (correct spelling Laodice) was named one of these names, he had been introduced to "the classics."This was very important to some families in Georgia. It's a good thing they changed this child's name a bit, because Laodice, the wife of Antiochus II was a very, very evil woman!
I would suggest you work on the family of his wife, rather than a Johnston in Georgia, to find out what county they lived in there.Folks couldn't travel too far to find a wife. The families may have been friends for a long time.
I know of several families that had sons named Richard.
Beverly Shuler